Pearls also have grades
According to the national standard GB/T16552 "Jewelry and Jade Name", GB/T16553 "Jewelry and Jade Identification" test samples, identification and classification:
According to different growth methods:
Can be divided into natural seawater pearls and natural freshwater pearls
Depending on the growing waters:
Can be divided into marine cultured pearls and freshwater cultured pearls
According to the presence or absence of beads:
Can be divided into nucleated cultured pearls and seedless cultured pearls
According to whether it is attached to the shell:
Can be divided into free cultured pearls and shell cultured pearls
How to choose pearls:
The classification of pearls is based on the quality of the pearls (seawater, fresh water), which are evaluated in terms of color, size, shape, gloss, finish, and bead thickness (nuclear pearl).
colour
The color of the pearl is divided into white, red, yellow, black and other five series, each series includes a variety of body color. Such as:
White series: pure white, milk white, silver white, porcelain white, etc.;
Red series: pink, light rose, lavender, etc.;
Yellow series: light yellow, beige, gold, orange, etc.;
Black series: black, blue black, green black, gray black, brown black, purple black, brown black, iron gray, etc.;
Others: purple, brown, cyan, blue, brown, purple, green, light blue, green, bronze, etc.
Pearls may have associated colors such as white, pink, rose, silver or green.
Pearls may have a faint color, and the halo is divided into a halo, a halo, and a faint.
Color description: mainly based on body color description, supplemented by color and halo description.
size
The round, round, and near-round pearls are represented by the smallest diameter, and the other shapes of the cultured pearls are represented by the largest size by the smallest size, and the bulk beads can be expressed by the aperture range of the pearl sieve.
Measure the size of the pearl (according to the calculation, the roundness of the pearl is a perfect circle, a circle or a near circle)
Shape level
Gloss level
Finish level
After comparison with standard samples, it is possible to have the following ambiguities:
Bead thickness level
Current detection methods include X-ray photography, OCT optical coherence tomography, bead thickness detection methods, and direct measurement methods.
Pearl classification
According to the quality factor of pearls, the pearls used for decoration are divided into two grades: jewelry-grade pearls and handicraft-grade pearls.
1. Jewelry-grade pearl quality factor minimum level requirement
Gloss level: medium (C).
Finish level: Pearl with a minimum size of 9mm (including 9mm): ç‘•ç–µ (D).
Pearl with a minimum size of 9mm or less: small clam (C).
Bead thickness (nuclear pearl): thin (D)
2. Crafts grade pearls
Handicraft-grade pearls that do not meet the requirements of jewelry-grade pearls.
Multi-grain pearl jewelry in pearl grading
This includes both the overall quality factor level determination and the match level determination.
a. Determine the individual quality factor level of each pearl in the jewelry;
b. separately count the percentage of pearls of the same level for each individual quality factor;
c. When a percentage of a certain quality factor above a certain level is not less than 90%, then the level is determined as the overall quality factor level;
d. Matching level determination
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